Epstein-Barr virus neutralizing and early antigen antibodies in multiple sclerosis

Evaluating the Clinical Utility of Epstein-Barr Virus Antibodies as Biomarkers in Multiple Sclerosis: A Systematic Review

BACKGROUND

EBV is a necessary but not sufficient factor in the pathophysiology of multiple sclerosis (MS). EBV antibodies to the nuclear antigen (EBNA1) and viral capsid antigen (VCA) rise rapidly prior to MS disease manifestations, and their absence has clinical utility with a high negative predictive value. It remains unclear whether EBV levels act as prognostic, monitoring, or pharmacodynamic/response biomarkers. Substantial literature on this topic exists but has not been systematically reviewed. We hypothesized that EBV levels against EBNA1 and VCA are potential prognostic and monitoring biomarkers in MS, and that patient population, MS clinical phenotype, and EBV assay method may play important roles in explaining variation among study outcomes.

METHODS

We systematically searched PubMed and EMBASE from inception to April 1, 2022. After removal of duplicates, records were screened by abstract. Remaining full-text articles were reviewed. Clinical and MRI data were extracted from full-text articles for comparison and synthesis.

RESULTS

Searches yielded 696 unique results; 285 were reviewed in full, and 36 met criteria for data extraction. Heterogeneity in sample population, clinical outcome measures, assay methods and statistical analyses precluded a meta-analysis. EBV levels were not consistently associated with clinical disease markers including conversion from CIS to RRMS, neurological disability, or disease phenotype. Studies using repeated-measures design suggest that EBNA1 levels may temporarily reflect inflammatory disease activity as assessed by gadolinium-enhancing Magnetic Resonance Imaging (MRI) lesions. Limited data also suggest a decrease in EBV levels following initiation of certain disease-modifying therapies.

CONCLUSION

Heterogeneous methodology limited generalization and meta-analysis. EBV antibody levels are unlikely to represent prognostic biomarkers in MS. The areas of highest ongoing promise relate to diagnostic exclusion and pharmacodynamic/disease response. Use of EBV antibodies as biomarkers in clinical practice remains additionally limited by lack of methodological precision, reliability, and validation.

Seroreactivity against lytic, latent and possible cross-reactive EBV antigens appears on average 10 years before MS induced preclinical neuroaxonal damage

BACKGROUND

Multiple sclerosis (MS) and presymptomatic axonal injury appear to develop only after an Epstein-Barr virus (EBV) infection. This association remains to be confirmed across a broad preclinical time range, for lytic and latent EBV seroreactivity, and for potential cross-reacting antigens.

METHODS

We performed a case-control study with 669 individual serum samples obtained before clinical MS onset, identified through cross-linkage with the Swedish MS register. We assayed antibodies against EBV nuclear antigen 1 (EBNA1), viral capsid antigen p18, glycoprotein 350 (gp350), the potential cross-reacting protein anoctamin 2 (ANO2) and the level of sNfL, a marker of axonal injury.

RESULTS

EBNA1 (latency) seroreactivity increased in the pre-MS group, at 15-20 years before clinical MS onset, followed by gp350 (lytic) seroreactivity (p=0.001-0.009), ANO2 seropositivity appeared shortly after EBNA1-seropositivity in 16.7% of pre-MS cases and 10.0% of controls (p=0.001).With an average lag of almost a decade after EBV, sNfL gradually increased, mainly in the increasing subgroup of seropositive pre-MS cases (p=8.10-5 compared with non-MS controls). Seropositive pre-MS cases reached higher sNfL levels than seronegative pre-MS (p=0.038). In the EBNA1-seropositive pre-MS group, ANO2 seropositive cases had 26% higher sNfL level (p=0.0026).

CONCLUSIONS

Seroreactivity against latent and lytic EBV antigens, and in a subset ANO2, was detectable on average a decade before the appearance of a gradually increasing axonal injury occurring in the last decade before the onset of clinical MS. These findings strengthen the hypothesis of latent EBV involvement in the pathogenesis of MS.

The Role of Viral Infections in the Onset of Autoimmune Diseases

Autoimmune diseases (AIDs) are the consequence of a breach in immune tolerance, leading to the inability to sufficiently differentiate between self and non-self. Immune reactions that are targeted towards self-antigens can ultimately lead to the destruction of the host's cells and the development of autoimmune diseases. Although autoimmune disorders are comparatively rare, the worldwide incidence and prevalence is increasing, and they have major adverse implications for mortality and morbidity. Genetic and environmental factors are thought to be the major factors contributing to the development of autoimmunity. Viral infections are one of the environmental triggers that can lead to autoimmunity. Current research suggests that several mechanisms, such as molecular mimicry, epitope spreading, and bystander activation, can cause viral-induced autoimmunity. Here we describe the latest insights into the pathomechanisms of viral-induced autoimmune diseases and discuss recent findings on COVID-19 infections and the development of AIDs.

Herpesviruses and the hidden links to Multiple Sclerosis neuropathology

Herpesviruses like Epstein-Barr virus, human herpesvirus (HHV)-6, HHV-1, VZV, and human endogenous retroviruses, have an age-old clinical association with multiple sclerosis (MS). MS is an autoimmune disease of the nervous system wherein the myelin sheath deteriorates. The most popular mode of virus mediated immune system manipulation is molecular mimicry. Numerous herpesvirus antigens are similar to myelin proteins. Other mechanisms described here include the activity of cytokines and autoantibodies produced by the autoreactive T and B cells, respectively, viral déjà vu, epitope spreading, CD46 receptor engagement, impaired remyelination etc. Overall, this review addresses the host-parasite association of viruses with MS.

The role of Epstein-Barr virus in the etiology of multiple sclerosis: a current review

Introduction: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. While its exact etiology is unknown, it is generally believed that MS is caused by environmental triggers in genetically predisposed individuals. Strong and consistent evidence suggests a key role of Epstein-Barr virus (EBV), a B lymphotropic human gammaherpesvirus, in the etiology of MS. Areas covered: This review summarizes recent developments in the field of EBV and MS with a focus on potential mechanisms underlying the role of EBV in MS. PubMed was searched for the terms 'Epstein-Barr virus' and 'multiple sclerosis'. Expert opinion: The current evidence is compatible with the working hypothesis that MS is a rare complication of EBV infection. Under the premise of a causative role of EBV in MS, it needs to be postulated that EBV causes a specific, and likely persistent, change(s) that is necessarily required for the development of MS. However, although progress has been made, the nature of that change and thus the precise mechanism explaining the role of EBV in MS remain elusive. The mechanism of EBV in MS therefore is a pressing question, whose clarification may substantially advance the pathophysiological understanding, rational therapies, and prevention of MS.

Prevalence of seropositivity of selected herpesviruses in patients with multiple sclerosis in the North of Jordan

Background

Multiple sclerosis (MS) is a neurological disease that is caused by an autoimmune response that results in the neuron’s demyelination in the central nervous system. The exact etiology of MS is not clear; however, several environmental and genetic factors are believed to participate in its initiation and development, including exposure to viruses. This study aims to investigate the association between the seropositivity and antibody titer of selected herpesviruses and MS in Jordanian MS patients.

Method

In this study, 55 MS patients and 40 age- and gender-matching apparently healthy volunteers were recruited from two main hospitals in the north of Jordan. MS patients were grouped into three types of MS based on the clinical presentation of the disease. Blood samples were collected from the participants and the IgG antibodies for human herpesvirus 6 (HHV-6), Epstein-Barr virus (EBV) nuclear antigen (EBNA), EBV viral capsid antigen (VCA) and varicella-zoster virus (VZV) were assayed by ELISA. The prevalence of seropositivity and the antibody level for each of the antibodies were compared between MS patients and controls and between the three types of MS.

Results

There was no significant difference in the prevalence of seropositivity and in the levels of antibodies for HHV-6, EBNA and VCA between MS patients and controls and between the three types of MS. In contrast, the number of seropositive patients and the level of IgG antibodies for VZV were significantly higher in MS patients compared to the control.

Conclusion

This study showed that patients with MS in the north of Jordan were more likely to be seropositive for VZV than the general population. Based on this finding, we recommend further studies to evaluate the seropositivity to VZV to be carried out in other parts of Jordan and the greater middle east to find out if there is a correlation between MS and previous infection with VZV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-020-01977-w.

Epstein-Barr Virus Infection in the Development of Neurological Disorders

Epstein-Barr Virus (EBV) is a ubiquitous human herpesvirus that contributes to the etiology of diverse human cancers and auto-immune diseases. EBV establishes a relatively benign, long-term latent infection in over 90 percent of the adult population. Yet, it also increases risk for certain cancers and auto-immune disorders depending on complex viral, host, and environmental factors that are only partly understood. EBV latent infection is found predominantly in memory B-cells, but the natural infection cycle and pathological aberrations enable EBV to infect numerous other cell types, including oral, nasopharyngeal, and gastric epithelia, B-, T-, and NK-lymphoid cells, myocytes, adipocytes, astrocytes, and neurons. EBV infected cells, free virus, and gene products can also be found in the CNS. In addition to the direct effects of EBV on infected cells and tissue, the effect of chronic EBV infection on the immune system is also thought to contribute to pathogenesis, especially auto-immune disease. Here, we review properties of EBV infection that may shed light on its potential pathogenic role in neurological disorders.

Antibodies to Human Herpesviruses in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Myalgic encephalomyelitis, also referred to as chronic fatigue syndrome (ME/CFS) is a debilitating disease characterized by myalgia and a sometimes severe limitation of physical activity and cognition. It is exacerbated by physical and mental activity. Its cause is unknown, but frequently starts with an infection. The eliciting infection (commonly infectious mononucleosis or an upper respiratory infection) can be more or less well diagnosed. Among the human herpesviruses (HHV-1-8), HHV-4 (Epstein-Barr virus; EBV), HHV-6 (including HHV-6A and HHV-6B), and HHV-7, have been implicated in the pathogenesis of ME/CFS. It was therefore logical to search for serological evidence of past herpesvirus infection/reactivation in several cohorts of ME/CFS patients (all diagnosed using the Canada criteria). Control samples were from Swedish blood donors. We used whole purified virus, recombinant proteins, and synthetic peptides as antigens in a suspension multiplex immunoassay (SMIA) for immunoglobulin G (IgG). The study on herpesviral peptides based on antigenicity with human sera yielded novel epitope information. Overall, IgG anti-herpes-viral reactivities of ME/CFS patients and controls did not show significant differences. However, the high precision and internally controlled format allowed us to observe minor relative differences between antibody reactivities of some herpesviral antigens in ME/CFS versus controls. ME/CFS samples reacted somewhat differently from controls with whole virus HHV-1 antigens and recombinant EBV EBNA6 and EA antigens. We conclude that ME/CFS samples had similar levels of IgG reactivity as blood donor samples with HHV-1-7 antigens. The subtle serological differences should not be over-interpreted, but they may indicate that the immune system of some ME/CFS patients interact with the ubiquitous herpesviruses in a way different from that of healthy controls.

Discrepancy of Serological and Molecular Patterns of Circulating Epstein-Barr Virus Reactivation in Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is characterized by B cell hyperactivation, production of autoantibodies and increased risk of B cell lymphomas. Serological profile of Epstein-Barr virus (EBV) reactivation and increase EBV DNA levels in exocrine glands are observed in pSS, but whether these abnormalities are accompanied with disturbed systemic EBV control or have any association with pSS activity remains to be investigated. In this observational study, we initially explored anti-EBV antibodies and cell-free DNA in 395 samples from a cross-sectional plasma collection of pSS patients included in ASSESS French national cohort. Results were assessed in relation with disease activity. Further, to assess cell-associated EBV DNA we organized a case-control study including 20 blood samples from pSS patients followed in University Hospital Center of Montpellier. Results were compared with matched controls. Robust response against EBV early antigen (EA) was observed in pSS patients with anti-SSA/B (Sjögren's syndrome A and B) and anti-SSA autoantibodies compared to anti-SSA/B negatives (P < 0.01 and P = 0.01, respectively). Increased beta-2 microglobulin, kappa and lambda light chains, and immunoglobulin G levels were more frequently observed in anti-EA seropositive pSS subjects compared to anti-EA negative subjects (P < 0.001; P = 0.001; P = 0.003, respectively). Beta-2 microglobulin was independently associated with anti-EA positivity in multivariate analysis (P < 0.001). Plasma cell-free EBV DNA and EBV cellular reservoir was not different between pSS patients and controls. We conclude that serological evidence of EBV reactivation was more frequently observed and more strongly associated with anti-SSA/B status and B cell activation markers in pSS. However, serological profile of EBV reactivation was not accompanied by molecular evidence of systemic EBV reactivation. Our data indicated that EBV infection remains efficiently controlled in the blood of pSS patients.

Differential serostatus of Epstein-Barr virus in Iranian MS patients with various clinical patterns

Background: Epidemiological evidence suggests a role of Epstein-Barr virus (EBV) in triggering the pathogenesis of Multiple Sclerosis (MS). The aim of this study was to assess the EBV-specific antibodies in MS patients with various clinical patterns and their association with the production of IFN-γ, IL-12, and IL-4 cytokines compared with healthy individuals.

Methods: We measured EBNA-1 IgG, VCA IgG, and production of IFN-γ, IL-12 and IL-4 cytokines in patients with different clinical patterns and healthy controls using ELISA method.

Results: There was a higher titer of anti-EBV antibodies in MS patients compared to healthy controls. SPMS patients generated higher EBNA-1 levels than those with RRMS and PPMS patients whereas; the level of VCA IgG was higher in the RRMS patients than PPMS. In PPMS patients, a significant increase was found in IFN-γ and IL-12 cytokines compared to other subtypes, whereas IL-4 cytokine had a decreased level compared to RRMS patients. Higher anti-EBV antibodies are associated with increased IL-12 cytokine in RRMS patients. However, no significant correlation was found between these antibodies and other secreted cytokines.

Conclusion: EBV infection is one of the strong risk factors for MS. Acting on these factors could be useful to decrease the incidence and disease exacerbation of MS. Study of the antibody levels to EBV virus could be useful for evaluating MS risk score in each clinical subtypes.

Epstein-Barr virus antibodies in serum and DNA load in saliva are not associated with radiological or clinical disease activity in patients with early multiple sclerosis

Objective

To investigate the association of Epstein-Barr virus (EBV) nuclear antigen-1 (EBNA-1) and viral capsid antigen (VCA) immunoglobulin (Ig)G antibodies in serum as well as EBV DNA load in saliva with radiological and clinical disease activity in patients with clinically isolated syndrome (CIS) and early relapsing-remitting MS (RRMS).

Methods

EBNA-1 and VCA immunoglobulin (Ig)G antibodies were determined in serum of 100 patients with CIS/early RRMS and 60 healthy controls. EBV DNA load was measured in saliva of 48 patients and 50 controls. Patients underwent clinical assessment with the Expanded Disability Status Scale (EDSS) and 3 Tesla magnetic resonance imaging at baseline and after a median of 20 months of follow-up (n = 63 for MRI, n = 71 for EDSS). The association of EBV parameters with occurrence of a second relapse, indicating conversion to clinically definite MS (CDMS), was evaluated over a median of 35 months of follow-up after the first clinical event (n = 89).

Results

EBNA-1 IgG antibody frequency (p = 0.00005) and EBNA-1 and VCA IgG antibody levels (p<0.0001 for both) were higher in patients than in controls. EBV DNA load in saliva did not differ between groups. Neither EBV antibody levels nor DNA load in saliva were associated with baseline or follow-up number or volume of T2-weighted (T2w) or contrast enhancing lesions, number of Barkhof criteria or the EDSS, or with the number of new T2w lesions, T2w lesion volume change or EDSS change on follow-up. Likewise, levels of EBV IgG antibodies in serum and DNA load in saliva were not associated with conversion to CDMS.

Conclusions

While these findings confirm the association of EBV infection with early MS, neither EBNA-1 nor VCA IgG antibodies in serum nor EBV DNA load in saliva were associated with radiological or clinical disease activity in patients with CIS/early RRMS. These data are compatible with the concept that EBV may be a trigger for MS acting very early during the development of the disease.

Epstein-Barr virus in multiple sclerosis

BACKGROUND/OBJECTIVES

Multiple sclerosis (MS) is an inflammatory disorder of the central nervous system. Many diseases are associated with Epstein-Barr virus (EBV) infection, such as infectious mononucleosis and many types of malignancies, and it is thought to be related to some diseases of autoimmune origin, such as rheumatoid arthritis, systemic lupus erythematosis, and others. The present study aimed to assess EBV in patients with MS.

PATIENTS AND METHODS

This case-control study was conducted from October 2012 to September 2013 on 75 MS patients and non-MS controls. Both were tested quantitatively for immunoglobulin G (IgG) antibodies against Epstein-Barr nuclear antigen-1 (EBNA1) and viral capsid antigen (VCA) using the enzyme linked immunosorbent assay technique.

RESULTS

Seventy MS patients (93.3%) were positive for EBNA1 IgG compared with 68 controls (90.7%). In MS patients, the mean EBNA1 IgG serum level was 310.91 (±131.05) U/ml; meanwhile, among controls the mean serum EBNA IgG level was 177.81 (±104.98) U/ml.All patients with MS were positive for VCA IgG, whereas only 60 (80.0%) controls were positive. In the MS group, the VCA IgG mean level was 302.19 (±152.11) U/ml compared with 167.94 (±111.79) U/ml in controls. The differences in the serum levels of both markers between the two groups were statistically significant (P<0.001).

CONCLUSION AND RECOMMENDATIONS

EBV proved to have a unique immunological pattern in MS patients when compared with non-MS controls. Further studies for more confirmation of the relation between EBV and MS on a large scale are recommended.

Fine specificity of the antibody response to Epstein-Barr nuclear antigen-2 and other Epstein-Barr virus proteins in patients with clinically isolated syndrome: A peptide microarray-based case-control study

We analyzed the fine specificity of antibodies to Epstein-Barr nuclear antigen-2 (EBNA-2) and other Epstein-Barr virus (EBV) proteins in 29 patients with clinically isolated syndrome (CIS, the first clinical manifestation of multiple sclerosis [MS]) and 29 controls with a peptide microarray containing 117 overlapping peptides representing the full-length EBNA-2 protein and 71 peptides from 8 further EBV proteins. While EBV peptide antibodies were elevated in CIS, suggesting that EBV contributes to MS early during disease development, they discriminated groups only slightly better than EBNA-1 antibodies. Thus, the additional value of EBV peptide antibodies as diagnostic biomarkers for CIS appears moderate.

Antibodies specific for Epstein-Barr virus nuclear antigen-1 cross-react with human heterogeneous nuclear ribonucleoprotein L

Epstein-Barr virus (EBV) is associated with multiple sclerosis (MS), and antibodies to the EBV nuclear antigen-1 (EBNA-1) are consistently increased in MS patients. The hypothesis of this study is that anti-EBNA-1 antibodies cross-react with a self antigen in MS patients. We affinity purified anti-EBNA-1 antibodies from human plasma, used the anti-EBNA-1 to immunoprecipitate antigens from human brain, and identified bound antigens with mass spectrometry. Anti-EBNA-1 consistently bound heterogeneous nuclear ribonucleoprotein L (HNRNPL). We expressed both the long and short isoforms of this protein, and verified with Western blots and ELISA that the long isoform cross-reacts with EBNA-1. Immunohistochemistry demonstrated that anti-EBNA-1 bound to an antigen in the nucleus of cultured rat central nervous system cells. ELISA demonstrated the presence of antibodies to HNRNPL in the plasma of both healthy controls and MS patients, but anti-HNRNPL was not increased in MS patients. We conclude that HNRNPL is an autoantigen which cross-reacts with EBNA-1. The relevance of this autoantigen to MS and other autoimmune diseases remains to be investigated.

The Role of Latently Infected B Cells in CNS Autoimmunity

The onset of multiple sclerosis (MS) is caused by both genetic and environmental factors. Among the environmental factors, it is believed that previous infection with Epstein–Barr virus (EBV) may contribute in the development of MS. EBV has been associated with other autoimmune diseases, such as systemic lupus erythematous, and cancers like Burkitt’s lymphoma. EBV establishes a life-long latency in B cells with occasional reactivation of the virus throughout the individual’s life. The role played by B cells in MS pathology has been largely studied, yet is not clearly understood. In MS patients, Rituximab, a novel treatment that targets CD20⁺ B cells, has proven to have successful results in diminishing the number of relapses in remitting relapsing MS; however, the mechanism of how this drug acts has not been clearly established. In this review, we analyze the evidence of how B cells latently infected with EBV might be altering the immune system response and helping in the development of MS. We will also discuss how animal models, such as experimental autoimmune encephalomyelitis (EAE) and murine gammaherpesvirus-68 (γHV-68), can be used as powerful tools in the study of the relationship between EBV, MS, and B cells.

Targeting Epstein-Barr virus infection as an intervention against multiple sclerosis

We here review contemporary data on genetic and environmental risk factors, particularly Epstein-Barr virus infection, for multiple sclerosis. There is an important immunogenetic etiological factor for multiple sclerosis. However, a general assumption is that immune defense genes are activated by the environment, basically by infections. We contend that the relationship between infectious mononucleosis and multiple sclerosis cannot be completely explained by genetics and inverse causality. Epstein-Barr infection as indicated by positive serology is an obligatory precondition for multiple sclerosis, which is a stronger attribute than a risk factor only. Data on events in the early pathogenesis of multiple sclerosis are cumulating from bio-banks with presymptomatic specimens, but there is only little information from the critical age when Epstein-Barr infection including infectious mononucleosis is acquired, nor on the detailed immunological consequences of this infection in individuals with and without multiple sclerosis. We discuss how focused bio-banking may elaborate a rationale for the development of treatment or vaccination against Epstein-Barr virus infection. A cohort in which intervention against Epstein-Barr infections was performed should be the object of neurological follow-up.

Epstein-Barr virus and multiple sclerosis: potential opportunities for immunotherapy

Multiple sclerosis (MS) is a common chronic inflammatory demyelinating disease of the central nervous system (CNS) causing progressive disability. Many observations implicate Epstein–Barr virus (EBV) in the pathogenesis of MS, namely universal EBV seropositivity, high anti-EBV antibody levels, alterations in EBV-specific CD8⁺ T-cell immunity, increased spontaneous EBV-induced transformation of peripheral blood B cells, increased shedding of EBV from saliva and accumulation of EBV-infected B cells and plasma cells in the brain. Several mechanisms have been postulated to explain the role of EBV in the development of MS including cross-reactivity between EBV and CNS antigens, bystander damage to the CNS by EBV-specific CD8⁺ T cells, activation of innate immunity by EBV-encoded small RNA molecules in the CNS, expression of αB-crystallin in EBV-infected B cells leading to a CD4⁺ T-cell response against oligodendrocyte-derived αB-crystallin and EBV infection of autoreactive B cells, which produce pathogenic autoantibodies and provide costimulatory survival signals to autoreactive T cells in the CNS. The rapidly accumulating evidence for a pathogenic role of EBV in MS provides ground for optimism that it might be possible to prevent and cure MS by effectively controlling EBV infection through vaccination, antiviral drugs or treatment with EBV-specific cytotoxic CD8⁺ T cells. Adoptive immunotherapy with in vitro-expanded autologous EBV-specific CD8⁺ T cells directed against viral latent proteins was recently used to treat a patient with secondary progressive MS. Following the therapy, there was clinical improvement, decreased disease activity on magnetic resonance imaging and reduced intrathecal immunoglobulin production.

Systematic review and meta-analysis of the sero-epidemiological association between Epstein Barr virus and multiple sclerosis

Background

A role for Epstein Barr virus (EBV) in multiple sclerosis (MS) has been postulated. Previous systematic reviews found higher prevalences of anti-EBV antibodies in MS patients compared to controls, but many studies have since been published, and there is a need to apply more rigorous systematic review methods.

Methodology/Principal Findings

We examined the link between EBV and MS by conducting a systematic review and meta-analysis of case-control and cohort studies that examined the prevalence of anti-EBV antibodies in the serum of cases and controls. We searched Medline and Embase databases from 1960 to 2012, with no language restriction. The Mantel-Haenszel odds ratios (OR) for anti-EBV antibodies sero-positivity were calculated, and meta-analysis conducted. Quality assessment was performed using a modified version of the Newcastle Ottawa scale. Thirty-nine studies were included. Quality assessment found most studies reported acceptable selection and comparability of cases and controls. However the majority had poor reporting of ascertainment of exposure. Most studies found a higher sero-prevalence of anti-EBNA IgG and anti-VCA IgG in cases compared to controls. The results for anti-EA IgG were mixed with only half the studies finding a higher sero-prevalence in cases. The meta-analysis showed a significant OR for sero-positivity to anti-EBNA IgG and anti-VCA IgG in MS cases (4.5 [95% confidence interval (CI) 3.3 to 6.6, p<0.00001] and 4.5 [95% CI 2.8 to 7.2, p<0.00001] respectively). However, funnel plot examination suggested publication bias for the reporting of the anti-EBNA IgG. No significant difference in the OR for sero-positivity to anti-EA IgG was found (1.4 [95% CI 0.9 to 2.1, p = 0.09]).

Conclusion/Significance

These findings support previous systematic reviews, however publication bias cannot be excluded. The methodological conduct of studies could be improved, particularly with regard to reporting and conduct of laboratory analyses.

Viruses and multiple sclerosis

Multiple sclerosis (MS) is a heterogeneous disease that develops as an interplay between the immune system and environmental stimuli in genetically susceptible individuals. There is increasing evidence that viruses may play a role in MS pathogenesis acting as these environmental triggers. However, it is not known if any single virus is causal, or rather several viruses can act as triggers in disease development. Here, we review the association of different viruses to MS with an emphasis on two herpesviruses, Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV-6). These two agents have generated the most impact during recent years as possible co-factors in MS disease development. The strongest argument for association of EBV with MS comes from the link between symptomatic infectious mononucleosis and MS and from seroepidemiological studies. In contrast to EBV, HHV-6 has been found significantly more often in MS plaques than in MS normal appearing white matter or non-MS brains and HHV-6 re-activation has been reported during MS clinical relapses. In this review we also suggest new strategies, including the development of new infectious animal models of MS and antiviral MS clinical trials, to elucidate roles of different viruses in the pathogenesis of this disease. Furthermore, we introduce the idea of using unbiased sequence-independent pathogen discovery methodologies, such as next generation sequencing, to study MS brain tissue or body fluids for detection of known viral sequences or potential novel viral agents.

Epstein-Barr virus neutralizing antibody levels and risk of multiple sclerosis

Previous infection with Epstein-Barr virus (EBV) and infectious mononucleosis are established multiple sclerosis (MS) risk factors, and elevated serum titers of anti-EBV nuclear antigen (anti-EBNA) antibodies in healthy adults are strongly correlated with future MS risk. In this prospective study, we investigated the association between EBV neutralizing antibodies and MS risk. MS risk tended to be higher in individuals with high titers of neutralizing antibodies compared to those with low titers (relative risk [RR] = 2.2, 95% confidence interval [CI] 0.97-5.1). This association was attenuated after adjustment for anti-EBNA1 IgG Ab titers (RR = 1.4, 95% CI 0.5-3.5). This preliminary finding warrants further study in a larger population.

More to come: humoral immune responses in MS

Interest in the role of B-cells in multiple sclerosis (MS) pathogenesis has increased, and a number of B-cell targeted therapies are currently in clinical trials. B-cells are key mediators of the humoral immune response, with roles including antibody production and acting as antigen presenting cells. Whilst previously, the presence of B-cells within MS plaques has been thought to be secondary to T-cell dysregulation, it is now becoming clear that B-cells play an independent role in disease. In this review we will discuss the potential role of B-cells in MS, how this influences our understanding of the disease, and potential therapeutic implications.

Combinatorial antibody library from multiple sclerosis patients reveals antibodies that cross-react with myelin basic protein and EBV antigen

Multiple sclerosis (MS) is a widespread neurodegenerative autoimmune disease with unknown etiology. It is increasingly evident that, together with pathogenic T cells, autoreactive B cells are among the major players in MS development. The analysis of myelin neuroantigen-specific antibody repertoires and their possible cross-reactivity against environmental antigens, including viral proteins, could shed light on the mechanism of MS induction and progression. A phage display library of single-chain variable fragments (scFvs) was constructed from blood lymphocytes of patients with MS as a potential source of representative MS autoantibodies. Structural alignment of 13 clones selected toward myelin basic protein (MBP), one of the major myelin antigens, showed high homology within variable regions with cerebrospinal fluid MS-associated antibodies as well as with antibodies toward Epstein-Barr latent membrane protein 1 (LMP1). Three scFv clones showed pronounced specificity to MBP fragments 65-92 and 130-156, similar to the serum MS antibodies. One of these clones, designated E2, in both scFv and full-size human antibody constructs, was shown to react with both MBP and LMP1 proteins in vitro, suggesting natural cross-reactivity. Thus, antibodies induced against LMP1 during Epstein-Barr virus infection might act as inflammatory trigger by reacting with MBP, suggesting molecular mimicry in the mechanism of MS pathogenesis.

Multiple sclerosis: are protective immune mechanisms compromised by a complex infectious background?

The immunological background of multiple sclerosis (MS) manifests as an altered reactivity against a diverse range of infections, particularly with the Epstein-Barr virus. Although this could be only an epiphenomenon of a more generalised dysfunction of the immune system in MS, it is also possible that a complex infectious background forms the basis of a specific immune dysregulation finally causing the disease. It is thus suggested that the complex infectious background bears the key for an understanding of the immune pathogenesis of the disease. It appears probable that improved standards of hygiene cause regulatory defects in the immune system, allowing the abnormal expression of human endogenous retroviral (HERV) genes. On the basis of epidemiological observations we describe how a failure of expansion or an eclipse of a subfraction of self-antigen-specific CD8(+) T cells mediating immune repair, and a deleterious mode of action of HERV gene products, could underlie the pathogenesis of MS.